We have to use earphone to enjoy the mp3(mp4) music,which is not very safe when driving. Now we can offer the transmitter of mp3(mp4) to car ,connect MP3 ,walkman to the car stereo wirelessly and you can enjoy the music freely withoutearphone in the car. Main Functions: Change the audio frequency signal into the FM signal, and then is emitted to the Stereo system to be played. What you need to do is to connect the sound equipments to this transmitter, and adjust radio frequency into the assignedfrequency. Then you can enjoy music Freely without earphone when driving for more safety. Features: 1.Change audio signal into FM signal transmitter wirelessly, and enjoy music in walkman via car radio without earphone. 2.Car wireless patent technology: making the disturbance from outside, the sound effect is wonderful, extreme music experience 3.Two FM channel 88.9MHZ,107.9MHZ, neednt change FM channel to make sound good. The good sound effect is stable. 4.Car sound transfer: Connected to many frequency equipments, like MP3\PDA\CD\DV\Portable DVD etc. 5.Fashionably, unique design and own outlook patent; 6.Radiation distance:only3-5meter(best effect)no electromagnetism disturbance, or no electromagnetism noise to the environmen